Morton Koopa Jr. is one of the Koopalings, a clan of seven members that are loyal to Bowser in the Super Mario series of games. While many people thought they were Bowser's children, an interview with Shigeru Miyamoto pointed out that they are not related at all. He has a gray shell, gray skin color and a white head, which has a star birthmark over his left eye. He was named after talk show host and singer-songwriter, Morton Downey Jr.
His first appearance was in Super Mario Bros. 3, where he is the boss of the second world. In Super Mario World, his appearance is altered slightly, with his color being green, and he is the boss of the second world. His next appearance isn't until New Super Mario Bros. Wii, then New Super Mario Bros. 2 and finally New Super Mario Bros. U. He also appeared in Mario & Luigi: Superstar Saga, as a boss in the final stretch leading up to Bowser